The aim of this research project is to develop new tissue (cell) culture models for the study of neuronal aging. Presently we have developed or are in the process of developing three tissue culture models: (a) dissociated cell cultures of adult mammalian (mouse, human) sensory and sympathetic ganglia, (b) explant cultures of adult mammalian (dog) retina, and (c) dissociated cell cultures of adult mammalian (mouse, rat) brain and spinal cord. These cultures will be employed for the studies of aging changes in neurons and of regeneraive ability of adult neurons.